Any Leaf Spring Technicians out there?

Submitted: Sunday, Mar 22, 2015 at 18:51

ThreadID: 117178 Views:3286 Replies:6 FollowUps:8

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IronMan

Question for the knowledge bank...

I am building a light duty on-road trailer similar in design to an Ezy Trailer folding trailer. I have an issue with the leaf springs.

I have come into the possession of a pair of new trailer type leaf springs which the previous owner had no use for and didn't mind me obtaining them (true!). The trailer they would have been used for is a dual axle and rated at 1500kg loaded, hence the springs are safe for 750kg per pair, perfect! BUT they are as stiff as anything! Crazy stiff. Rock hard. Hard enough that their stiffness and the usual bouncing on the road may damage the folding parts.

They are four leaves. No 1 is the top leaf, eye to eye. No 2 is shorter, No 3 shorter still and with the riveted clamp devices, and No 4 is the shortest leaf and is retained with the centre bolt. I have replaced this bolt and removed (but kept) No 4 leaf. Leaves are about 5mm thick and the spring is 50mm wide.

My question is, what leaves should I remove to soften the spring pack? Reducing the capacity isn't a problem, the trailer won't be rated to 750kg loaded when I comply it.

I can safely dismantle the remaining leaves at work without damaging the heat treatment of the leaves.

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Reply By: Peter_n_Margaret - Sunday, Mar 22, 2015 at 19:04

Reply By: Ron N - Sunday, Mar 22, 2015 at 19:37

Reply By: pop2jocem - Sunday, Mar 22, 2015 at 19:39

Sunday, Mar 22, 2015 at 19:39

Peter's advice sounds reasonable but personally I would be like to know what weight and exactly what type of load you intend carrying before recommending doing away with the spring packs altogether.

Also don't forget that leaf springs rely on the friction between the leaves for dampening so if the load is very light and you remove too many you are going to get a lot of bouncing happening which may or not be important depending on what you are transporting.

Cheers
Pop

AnswerID: 551416

Follow Up By: Bob Y. - Qld - Sunday, Mar 22, 2015 at 19:47

Sunday, Mar 22, 2015 at 19:47

Ironman,

Agree with Pop about lack of dampening with only one leaf.

Something like these items, with one leaf, might be the go. Have used them before, and they seem to work alright.

Aeon Rubber Springs

Bob

Seen it all, Done it all.
Can't remember most of it.

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FollowupID: 836880

Follow Up By: IronMan - Sunday, Mar 22, 2015 at 20:35

Sunday, Mar 22, 2015 at 20:35

After reading the replies (thank you all!) I should have given more information.

The "folding special" is more just a project, but I want it to WORK. It will be only used to carry "stuff", lawn clippings to the tip, a couple of hundred kilo's on holidays on-road. As well as the springs, I also already have wheels and tyres, 6.00x9" 6 ply, sometimes found on boat trailers. 13" Holden or similar would have been ideal but when they're free...

My in-use 7x4 box was also built by me and it's a testimony that IronMan tends to over build things. The bloody thing is indestructible, but it's also heavy and a bit over-trailer for what i'll use it for. So when I finish my project I'll sell it.

For the project, I have bought the correct front and rear spring hangers and a light duty axle, and have hubs and bearings.

FollowupID: 836884

Follow Up By: Life Member - Terry 80FTE - Sunday, Mar 22, 2015 at 21:07

Sunday, Mar 22, 2015 at 21:07

Name like "IronMan" you should know about suspension ;)
You are probable best to build it using the springs as is, load it to your capacity and test tow/bounce it to see how it performs.
It would help to know the spring length, we'll start by assuming (dangerous) about 800mm
If to tight, then remove no.3 leaf first and retry,
I prefer softer springs, but with shockers and bump stops.
With little wheels you'll need to keep an eye on the wheel bearings and tyres.
Good luck with your project,

Cheers